The Porsche M44.50 Petrol is a 2,687 cc, water‑cooled inline‑four engine produced between 1999 and 2002. It featured a dual overhead cam (DOHC) layout and Bosch Motronic ME7.1 electronic fuel injection, delivering 201 PS (148 kW) with 270 Nm of torque. The compact inline‑four architecture was derived from the Audi-developed EA827 lineage but extensively re-engineered by Porsche for increased displacement, reinforced internals, and enhanced mid-range response—critical for the Boxster S 2.7’s elevated performance role.
Fitted exclusively to the Porsche Boxster (986) S 2.7 variants, the M44.50 was engineered for spirited driving with emphasis on throttle linearity, exhaust acoustics, and thermal resilience. Emissions compliance in European markets was achieved through three-way catalytic converters and dual oxygen sensor feedback, allowing adherence to Euro 3 standards from launch.
One documented concern is intermediate shaft (IMS) bearing wear, highlighted in Porsche Technical Bulletin PTB/99/12. This issue stems from marginal lubrication of the single-row sealed ball bearing supporting the intermediate shaft that drives the camshafts. Although displacement increased over the M44.05, IMS design remained unchanged until the 2000 model year, when Porsche introduced a dual-row bearing to improve durability under sustained high-RPM operation.
All models (1999–2002) meet Euro 3 emissions standards in European markets (KBA Type Approval #KBA/986/3459).
The Porsche M44.50 Petrol is a 2,687 cc water‑cooled inline‑four engineered for mid‑engine sports roadsters (1999–2002). It combines Bosch Motronic ME7.1 electronic fuel injection with a DOHC 16-valve architecture to deliver linear power, strong mid-range torque, and high-revving character. Designed to meet Euro 3 emissions from launch, it balances performance with regulatory compliance through catalytic and closed-loop engine management.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,687 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 82.5 mm × 82.0 mm | |
| Power output | 201 PS (148 kW) | |
| Torque | 270 Nm @ 4,750 rpm | |
| Fuel system | Bosch Motronic ME7.1 electronic fuel injection | |
| Emissions standard | Euro 3 | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water‑cooled (aluminum radiator with thermostatic control) | |
| Turbocharger | None | |
| Timing system | Chain‑driven DOHC with intermediate shaft (IMS) | |
| Oil type | 10W‑60 semi‑synthetic (Porsche A40 spec) | |
| Dry weight | 142 kg |
The DOHC inline‑four provides crisp throttle response and strong mid-range torque ideal for a sports roadster but requires strict adherence to oil change intervals and quality to prevent intermediate shaft (IMS) bearing wear. Use of 10W-60 semi-synthetic oil meeting Porsche A40 spec is critical for high-temperature film strength and IMS lubrication. Cold starts below 5°C should be followed by 5–8 minutes of gentle warm-up. The ME7.1 system requires OEM-spec oxygen sensors and fuel pressure regulators—non-compliant parts cause mixture instability and catalytic converter damage. Pre-2000 engines (early 1999 production) use single-row IMS bearings; 2000+ units use dual-row bearings per Porsche bulletin PTB/99/12.
Oil Specs: Requires 10W-60 semi-synthetic oil meeting Porsche A40 specification (Porsche Tech Bulletin PTB/99/12). ACEA A3/B3 oils are insufficient for IMS protection.
Emissions: All M44.50 variants meet Euro 3 standards across all production years (1999–2002) as confirmed by KBA Type Approval #KBA/986/3459.
Power Ratings: Measured under DIN 70020 standards. Output requires 98 RON fuel and optimal catalytic converter function (Porsche TIS Doc. P986‑01B).
Porsche Technical Information System (TIS): Docs P986‑99A, P986‑99C, P986‑01B
KBA Type Approval Database (KBA/986/3459)
DIN 70020 Engine Power Measurement Standard
The Porsche M44.50 Petrol was used exclusively in Porsche's Boxster (986) S platform with mid‑engine longitudinal mounting and no external licensing. This engine powered only the 2.7L S variant and received a key internal update in 2000 with the introduction of the dual-row intermediate shaft (IMS) bearing, creating a critical service distinction. All adaptations are documented in OEM technical bulletins.
Engine code is stamped on the left side of the engine block near the exhaust manifold (Porsche TIS P986‑99A). The 7th–8th VIN digits are '98' for all 986 Boxsters; the 10th digit indicates model year. Early 1999 (VIN 'X') engines use single-row IMS bearings; 2000–2002 (VIN 'Y', '1', '2') use dual-row bearings. The M44.50 can be visually distinguished from the 2.5L M44.05 by larger intake runners, secondary air injection pipes, and black cam covers with red timing marks. Engine serial number prefix '654.50' confirms displacement and variant.
The M44.50 Petrol's primary reliability risk is intermediate shaft (IMS) bearing failure in early 1999 units, with elevated incidence in high-RPM or track use. Porsche internal durability reports from 2000 noted a significant share of early Boxster S engines requiring IMS replacement before 100,000 km under aggressive driving, while KBA field audits confirmed IMS as a leading cause of engine seizure in 1999 production. Extended oil change intervals and incorrect viscosity reduce lubrication margin, making oil quality and IMS design critical.
Analysis derived from Porsche technical bulletins (1999–2002) and Kraftfahrt-Bundesamt (KBA) failure statistics (2000–2008). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE M-44-50.
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